SQL Self Join

SQL Self Join is used to join a table with itself, calling it Unary relationships. Each row of the table is associated with itself and every other row in the table.



Self Join Syntax :

The syntax of the Self Join is −

SELECT column-name(s)
FROM table1 T1, table1 T2
WHERE condition;

SQL Self Join Example :

Consider the Customer table with the following records -

TEST CASE 1 :-Let us join these two tables using the Self JOIN as follows

SELECT  a.ID, b.Name, a.Salary
FROM Customer a, Customer b
WHERE a.Salary < b.Salary;

The result for the respective sql query is as follows −

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